Evans was referring to a recent controversy in which Congressman John Lewis called Trump an "illegitimate" president.

Trump responded on Twitter, calling Lewis "all talk" and "no action."

That has prompted a wave of support for Lewis, a civil rights leader and Presidential Medal of Freedom honoree.

As of Monday night, about 40 Democrats in Congress said they were skipping the inauguration. So far, Evans and Boyle are the only lawmakers from Pennsylvania.

"The president-elect is attempting to take away healthcare from my constituents and I'm truly concerned about that," Evans told CBSPhilly.

"Secondly, in terms of the Russian hacking, I think that should be taken serious and should be investigated by Democrats and Republicans alike," he said to the TV station. "Last, but not least, his attack on Congressman John Lewis who is one of my heroes. John Lewis is all about action."

In a statement Monday, Boyle called Trump a "unique threat" to the Constitution and country.

Boyle, who said he believes in the peaceful transfer of power, said after two months of contemplation, he decided he can't participate in the inaugural celebration.

"I accept the decision of the people," Boyle said. "I respect it. But I will not celebrate it."

Boyle on Saturday responded to Trump's tweets about Lewis, saying, "You sir are not half the man he is."